Worldwide Interoperability for Microwave Access (WiMAX) is a wireless Metropolitan Area Network (MAN) technology based on IEEE802.16. The radio side of the WiMAX network is a wireless MAN access technology based on IEEE802.16d/e, and is based on the physical layer technology of Orthogonal Frequency Division Multiplexing (OFDM) technology and OFDM Access (OFDMA), and can resist multi-path fading effectively. In the case of best channel fading, the transmission rate approaches 75 Mbps.
The logical architecture of the WiMAX network is shown in FIG. 1. The whole WiMAX network includes the following three parts:
(1) Terminal. A terminal includes a Subscriber Station (SS) or Mobile Station (MS), through which the terminal accesses the WiMAX network.
(2) Access Service Network (ASN). An ASN is defined as a network function set that provides radio access services for a WiMAX terminal. An ASN includes two elements: a Base Station (BS) and an ASN Gateway (ASN-GW). The BS provides L2 connection and radio resource management for the BS and the MS, and the ASN-GW provides client functions in authentication, authorization and accounting of the MS, and provides the L3 information relay functions (such as IP address allocation) and intra-ASN handover for the MS.(3) Connectivity Service Network (CSN). A CSN is defined as a network function set that provides IP connection access services for a WiMAX terminal. A CSN includes logical entities such as PrePayment Service (PPS) server and Authentication, Authorization and Accounting (AAA) server, and provides these functions: IP address allocation for MS, Internet access, AAA proxy or server, and terminal-based authorization control.
With the requirement of opening network services, the WiMAX network introduces a third-party application interface that can open WiMAX network services to a third-party application interface inside or outside the network, namely, a Universal Service Interface (USI). Through a USI system, the WiMAX network can provide service interfaces for an Application Service Provider (ASP) or internet Application Service Provider (iASP). By invoking service capabilities provided by the USI, the ASP or iASP can apply the services open to WiMAX access terminals, and can provide individualized services for WiMAX access terminals more conveniently through an ASP network or Internet. The service capabilities opened by the WiMAX network through a USI system include: Quality of Service (QoS), location service, multicast and broadcast services, terminal information query, and terminal authentication.
FIG. 2 is a network reference model of a USI system. In the USI system, the MS, ASN and the CSN are three major parts of the WiMAX network, and the ASP/iASP is an application service provider independent of the WiMAX network. As shown in FIG. 2, the USI system is located in a CSN, and interacts with the ASP/iASP through a U1 interface. Optionally, a USI system interacts with an AAA server, a message server, and a location server within the CSN. The MS uses the existing Internet interface (such as HTTP) to interact with the ASP/iASP.
Within a WiMAX network, the terminal has a unique internal identity, and the internal identity is stored in an AAA server of the CSN. Based on this internal identity, the WiMAX network provides its capabilities and services. For safety and privacy, the internal identity is not disclosed to any entity outside the WiMAX network. In order to provide a specific terminal with services based on WiMAX USI system capabilities, the ASP/iASP needs to identify the identity of the terminal inside the WiMAX network through the USI identity of the terminal so that the WiMAX network can provide services based on the internal identity.
The existing protocol does not define how to register a terminal in a USI system after the terminal roams to a remote area; the prior art does not enable registration in a USI system when the terminal is in a roaming state, which further affects the service implementation; moreover, after the terminal roams to a remote area, USI registration cannot be triggered as required. If the terminal is registered in a USI system of the home network, the USI system in the visited network is unable to obtain the USI registration information of the terminal in the home network, which affects implementation of certain services such as broadcast service which is available only from the visited network rather than the home network.